WasteExpo 2017: Odors and options

Odors aren’t an easy environmental issue to quantify, but they are responsible for 50 percent of air quality complaints. Odors aren’t even recognized by the U.S. Environmental Protection Agency (EPA) because a number of molecules and substances can cause them. But speakers at WasteExpo 2017, in New Orleans, did not seem deterred by this and offered many solutions to help identify and resolve the stink.

Thomas Rappolt, office director and vice president, SCS Engineers, Long Beach, California, noted while odors can be unpleasant, rarely do they have physiological impacts. Sometimes stomach aches and headaches can happen, but he said, odors are “very real” to those who experience them.

Measuring odors can be done by evaluating a number of factors. These factors include intensity, character and hedonic tone, which is the relative pleasantness or unpleasantness of the odor. A number is assigned and the higher the number, the more severe the odor.

Pinpointing where the odor is coming from at a landfill can also be done. Daily cover does not eliminate all gasses and final cap extraction wells aren’t always as efficient as they need to be depending on wear.  

Rappolt recommends an odor panel. Sometimes it is determined that the section of landfill getting the complaints might not have as high a number reading as other sections, it could just be that the odor character has changed and people noticed.

James Walsh, president and CEO of SC, said municipal solid waste, special waste, biosolids, construction and demolition debris, all can create odors from the gases they emit.

He said, hydrogen sulfide is probably the biggest component of odors, but about five compounds are the most prevalent odor-causing compounds in landfills. Engineered controls can help.

Landfill liners made with ethylene vinyl alcohol (EVOH) tend to allow less gases to escape than those made from high-density polyethylene (HDPE), according to Walsh. In fact, he said, 60 times more gases escape through an HDPE cap. As well if the gas collection system isn’t operating well, a landfill could get a gas leak under the cap which creates a “whale” of landfill gas.

Laura Haupert, director of research and development, OMI Industries, Zurich, Illinois, also described some challenges with landfill gas. “Gasses go where they want to go. Hate to be near other gases, they are going to want to go out.”

In addition there are many sources of odors from organics to construction to yard waste and no one knows how long the odor has existed in the waste before it enters the landfill.

Weather also is a factor in the odors. Rain can cause bacterial growth that reacts with some chemical compounds. Heat also creates more bacteria and volatile organic compounds (VOCs). Wind can also carry the odor into neighborhoods.

Methods of control includes tire and truck washes, sludge trucks, gas collection systems, covers and sprays.

Portable system are designed to work around the working face of the landfill. Oscillating fans mist along working face and keep odors down that way. Perimeter systems also are used.

Kendra Sherman, an attorney with Squire Patton & Boggs, spoke about odor litigation. She recommended that when a notice is given about a complaint or violation to respond to the agency, and have constant dialogue.

WasteExpo 2017 was May 8-11 at the Ernest N. Morial Convention Center in New Orleans.